Survey of Indiana streams for sensitivity to acid deposition

The purpose of this study is to determine what effects, if any, acidic deposition has on stream chemistry in Indiana. Twelve streams in southern Indiana (six south of Lake Monroe, three south of St. Croix and three north of New Albany) were chosen for this purpose. The selection criteria consisted of soil characteristics (e.g., non-calcareous soil), land usage of the watershed (no agriculture, grazing, feedlots or urbanization) and accessibility of the headwaters. From mid-July to mid-August six samples were taken from each stream. Measurements included alkalinity, flow, temperature, pH, and conductivity. The concentration of a number of anions and cations, including sulfate, nitrate, calcium, and magnesium, were determined by ion chromatography and atomic absorption spectroscopy. All of these variables were then analyzed for correlation with rainfall events and emissions inventory. (DBO)